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64 votes
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What are Channel Factories and how do they work?

What are Channel Factories? In short, Channel Factories are payment channels that can be used to create more payment channels. That sounds weird, but it's really pretty simple: In a regular payment ...
David A. Harding's user avatar
21 votes
Accepted

What is the minRelayTxFee?

The minRelayTxFee specifies a feerate acting as a lower bound for a node's mempool. A node will not admit unconfirmed transactions below that feerate to its mempool and thus will not relay them to its ...
Murch's user avatar
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19 votes
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Why is coinbase mentioned in a BIP?

The coinbase mentioned in BIP34 is not the company; it is referring to the first transaction in a Bitcoin block (which is special as it is allowed to bring new currency into circulation). Coinbase-the-...
Pieter Wuille's user avatar
17 votes

When bitcoin forks, how do they decide which fork gets the original name?

One might think that the network maintaining the same consensus rules would be considered the original, and the project introducing a consensus rule change and thus creating a new network would be ...
Murch's user avatar
  • 75.4k
16 votes

What is the difference between a miner and a full node?

A 'full node' is a participant on the network that has independently validated the complete copy of the blockchain, and thus has verified all transactions since the beginning. This requires about ...
Michail Wilson's user avatar
16 votes

What is meant by transaction 'pinning'?

Transaction pinning happens when: I broadcast a transaction that signals opt-in RBF the transaction does not get confirmed because the feerate is too low someone else broadcasts a new (child) ...
jnewbery's user avatar
  • 1,060
15 votes

Replace-by-Fee vs Child-pays-for-Parent?

Replace-by-fee means transactions spending the same coin to the same addresses are not considered double-spends by the network and are still relayed, as long as they pay a higher fee than the ...
maservant's user avatar
  • 1,031
13 votes

What is meant by Bitcoin dust?

To understand 'dust' you must understand a few things: Firstly, a UTXO is an unspent transaction output. This is essentially a piece of bitcoin somewhere on the blockchain that is unspent. To create ...
Noel O'Donnell's user avatar
12 votes
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What is the difference between "native segwit" and "bech32"?

TL;DR: Native segwit refers to segwit outputs without P2SH-wrapper. Bech32 is the address format used to represent native segwit-v0 locking scripts. Wrapped segwit vs native segwit When segwit ...
Murch's user avatar
  • 75.4k
12 votes

Is it correct to say that Bitcoin has a virtual machine in the same way as Ethereum does?

"Virtual machine" in this context is really just a fancy word for bytecode interpreter. Bitcoin's script language is certainly far simpler than Ethereum's EVM, and its functionalities are in ...
Pieter Wuille's user avatar
11 votes

What is a nonce?

Nonce is a 32 bit arbitrary random number that is typically used once. In Bitcoin's mining process, the goal is to find a hash below a target number which is calculated based on the difficulty. Proof ...
abeikverdi's user avatar
11 votes
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Redeem script. script hash, witness script and witness program

The scriptPubKey is the script as it is placed in the transaction output. The redeemScript (P2SH only) is the script pushed as the last scriptSig item. In P2SH scripts, the scriptPubKey is equal to ...
Pieter Wuille's user avatar
10 votes
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What is sigop (signature operation)?

A sigop is script opcode which performs a signature check. That includes OP_CHECKSIG, OP_CHECKSIGVERIFY, OP_CHECKMULTISIG, and OP_CHECKMULTISIGVERIFY. This concept matters because of a consensus rule ...
Pieter Wuille's user avatar
9 votes
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What does "lock time" mean?

A specified locktime indicates that the transaction is only valid after a given blockheight. Since the locktime field indicated is 419382 and currently the latest blockheight as of 12th July 2016 1108 ...
rny's user avatar
  • 2,418
9 votes

What are tainted coins exactly?

The term "Tainted Coins" is often misinterpreted as a measure of provenance. That's understandable considering the traditional definition of the word "tainted" coupled with the reality that many ...
Rob Guthm's user avatar
  • 101
9 votes

What are checkpoints?

Update on this as of time of writing, just to clarify more specifically upon the other answer: dependence on checkpoints in the security model has been significantly reduced, they are only used in one ...
meshcollider's user avatar
  • 11.8k
9 votes

What does TLV stand for?

TLV stands for type-length-value. It's an encoding scheme used when protocols allow for optional elements in their messages. The type is a label telling you what field you're looking at, the length ...
Murch's user avatar
  • 75.4k
8 votes

What is an "unspent output"?

Bitcoin is a distributed system that enables users to receive, store, and send money. Value is transmitted by submitting a payment order to the network called a transaction. Transactions are ...
Murch's user avatar
  • 75.4k
8 votes
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What is the difference between on-chain scaling and off-chain scaling?

Note, I use scaling, capacity, and scalability as follows: Scaling: Growing the network's utility in any fashion. Capacity: The number of payments that can be processed on the network. Scalability: ...
Murch's user avatar
  • 75.4k
8 votes

What the difference between old segwit (3) and new segwit address (bc)?

The difference lies in the encoding and the underlying representation in the transaction data stored on the blockchain. The 3-segwit addresses are known as P2SH-P2WPKH or P2SH-P2WSH. This stands for ...
Raghav Sood's user avatar
8 votes
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What are the scriptPubKey, scriptSig, redeem script and witness for the various output types?

This was answered during the Bitcoin Core PR review club on July 7th 2021 hosted by Gloria Zhao (who also provided this table). The <public key> in the P2TR (key path) and P2TR (script path) ...
Michael Folkson's user avatar
8 votes
Accepted

What is signature grinding?

The serialization format used for ECDSA signatures requires 33 bytes to encode an r-value that falls into the higher half of the range, but only 32 bytes to encode one falling into the lower half of ...
Murch's user avatar
  • 75.4k
8 votes
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What is the difference between blocksonly and block-relay-only in Bitcoin Core?

While both of these disable transaction relay, they are conceptually used for different purposes: Block-relay-only connections (see this post for more details) are hard-to-detect connections with the ...
Lightlike's user avatar
  • 636
7 votes
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What is the meaning of the term "full-node"?

Fully validating nodes ("full nodes") are clients that have validated the whole blockchain self-sufficiently and enforce all of the rules of Bitcoin on any data they receive. Therefore, they cannot be ...
Murch's user avatar
  • 75.4k
7 votes

Are BTC and Bitcoin Core the same?

Kind of. People who call Bitcoin "Bitcoin Core" are referring to Bitcoin. They will also use the name "Bitcoin Legacy". but calling Bitcoin "Bitcoin Core" or "Bitcoin Legacy" is misleading. Bitcoin ...
Ava Chow's user avatar
  • 70.5k
7 votes
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What does PSBT stand for?

It stands for "Partially Signed Bitcoin Transaction". Bitcoin Core's documentation describes it as: PSBT is an interchange format for Bitcoin transactions that are not fully signed yet, ...
Geremia's user avatar
  • 4,636
6 votes

What is the minRelayTxFee?

'minRelayTxFee' is the node's minimum reward (BTC/KB) for a transaction "transmission" (relay). In the p2p network there could be a node (A) with a minRelayTxFee setted at 0,0001 and a node (B) with a ...
Antony Zappacosta's user avatar
6 votes

What does the blockchain represent?

The blockchain is the complete transactional history of Bitcoin. It collects every transaction performed in blocks which each are linked to their predecessor block. By parsing the complete blockchain,...
Murch's user avatar
  • 75.4k
6 votes
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Is a P2WPKH address synonymous with a Bech32 address?

are P2WPKH and Bech32 synonyms now? No. Bech32 is also used for P2WSH addresses. Native segwit and Bech32 are synonyms. Is there such a thing as Base58 P2WPKH address? No.
Ava Chow's user avatar
  • 70.5k
6 votes
Accepted

What the difference between old segwit (3) and new segwit address (bc)?

There's no big difference for users between the two. The fee is lower while using native Segwit address (bech32), and the address format differs. Let's look at the motivations of bech32 address ...
Tailer's user avatar
  • 3,669

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